The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Centrifugal Pendulum Vibration Absorbers (CPVAs) are typically used to reduce torsional vibrations in rotating machine components. For example, a rotating member such as a shaft includes several CPVAs arranged symmetrically about a rotational axis of the shaft. Each CPVA has a pendulum mass that is constrained in movement along a specific path relative to the rotational axis of the shaft. Each pendulum mass oscillates or moves back and forth along the path as the shaft operates. The movement of the pendulum masses about the paths counteract torque fluctuations that are created as the shaft operates, which reduces the torsional vibration of the shaft.
When the shaft comes to a rest, the pendulum masses stop moving and tend to settle in different positions in relation to the rotational axis of the shaft. However, allowing the pendulum masses to settle in different positions may increase the time it takes for the pendulum masses to come to a rest, contributes to instability of the shaft, and may also lead to unwanted noise as the shaft begins to rotate again.
Another known problem with CPVAs occurs when the shaft operates at lower rotational speeds. Specifically, movement of the pendulum masses tends to produce unwanted noises, such as rattling, as the shaft operates at a relatively slow speed. All of the issues discussed above can be problematic in automotive applications, especially as the engine starts up and comes to a stop.
While CPVAs achieve their intended purpose, the need for new and improved CPVA configurations which exhibit improved performance, especially from the standpoint of noise, is essentially constant. Accordingly, there is a need for an improved, cost-effective, and quieter CPVA.